TMZ reported Thursday that Ball and several teammates were involved in a fight at a home off-campus "roughly one week before Ball was jumped on campus." TMZ cites law enforcement sources that indicate Ball was present at the home and "may have participated in beating up a non-football player."

Ball struck back via Twitter with a one-line denial: "The report that I was involved in a fight is totally false."

Coach Bret Bielema said Wednesday that Ball came to his office Thursday afternoon and will be with the team when training camp begins.

However, durring the taping of his television show Thursday, Bielema said Ball will not be an active participant when Wisconsin opens camp this Sunday. Bielema did not say when he thought Ball would be able to participate.

Ball was attacked by multiple assailants at 2 a.m. Wednesday according to Madison police and suffered a concussion. He was treated and released from a local hospital.

Witnesses told police Ball did exchange words with his assailants -- reportedly five men who kicked and struck Ball -- before the attack.

Ball was the leading rusher in the FBS last season with 1,923 yards and 33 touchdowns. The Heisman Trophy finalist opted to return to the defending Big Ten champion Badgers for his senior season rather than enter the NFL draft.

Gen. David Petraeus pleaded guilty to federal charges Tuesday to end a probe into whether he provided classified information to his mistress when he was CIA director, according to a U.S. official briefed on the matter.